Sport Concussion Assessment Tool: baseline and clinical reference limits for concussion diagnosis and management in elite Rugby Union

Objectives Rugby Union has adapted the Sports Concussion Assessment Tool (SCAT) into an abridged off-field concussion screen and complete SCAT is used during diagnostic screens performed after head impact events. No firm guidelines exist as to what should be considered “abnormal” warrant further evaluation. This study evaluates performances in 13,479 baseline assessments, proposes clear reference limits for each sub-component of SCAT5. Baseline are proposed guide management testing by identifying abnormal sub-tests, enhancing clinical validity screens, while identified support diagnosis when no available. Design Cross sectional census sample. Methods SCATs from 7565 elite male rugby players were evaluated. sub-test result achieved approximately 5% population, references corresponded score close possible 50% cohort. Results Players reported symptoms 35% (95% CI 1.29–1.42) more frequently SCAT5 than SCAT3 assessments (mean 1.4 ± 2.7 vs 1.0 2.4). Ceiling effects many cognitive sub-tests within SCAT. Clinical corresponding worst performing 5th percentile 50th described. Conclusions Targeted re-testing repeated according limits, a conservative limit supports settings.